Methods and apparatus for reducing sputtering of a grounded shield in a process chamber

ABSTRACT

Methods and apparatus for physical vapor deposition are provided herein. In some embodiments, a process kit shield for use in a physical vapor deposition chamber may include an electrically conductive body having one or more sidewalls defining a central opening, wherein the body has a ratio of a surface area of inner facing surfaces of the one or more sidewalls to a height of the one or more sidewalls of about 2 to about 3.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending U.S. patent applicationSer. No. 13/798,021, filed Mar. 12, 2013, of which is hereinincorporated by reference.

FIELD

Embodiments of the present invention generally relate to physical vapordeposition processing equipment.

BACKGROUND

In a physical vapor deposition (PVD) chamber, a region exists between aplasma and its surrounding surfaces, such as powered, grounded, orfloating electrodes, referred to as the dark space region or sheathregion. A typical PVD chamber may use a radio frequency (RF) powersource to form the plasma. As the frequency of the RF source increases,the plasma density increases and the sheath width decreases. Theinventors have observed that this phenomenon can negatively affect thedesired plasma geometry at the plasma boundary and cause secondaryplasma ignition in unwanted areas. In certain PVD chambers, a groundedelectrode (referred to herein as the grounded shield) acts as the maincurrent return path from the plasma back to the generator. In the caseof RF driven plasma discharges, the plasma potential can be in theregion of a few tens to a few hundred volts positive with respect to thegrounded shield. This potential difference coupled with the highplasma-ion density can cause undesirable sputtering of the groundedshield, which can be a source of contamination of the chamber and/or thesubstrate.

Accordingly, the inventors have provided methods and apparatus forreducing the sputtering of a grounded shield in a process chamber.

SUMMARY

Methods and apparatus for physical vapor deposition are provided herein.In some embodiments, a process kit shield for use in a physical vapordeposition chamber may include an electrically conductive body havingone or more sidewalls defining a central opening, wherein the body has aratio of a surface area of inner facing surfaces of the one or moresidewalls to a height of the one or more sidewalls of about 2 to about3.

In some embodiments, a substrate processing apparatus may include achamber body having a substrate support disposed therein; a targetcoupled to the chamber body opposite the substrate support; an RF powersource to form a plasma within the chamber body; and a grounded shieldhaving an inner wall disposed between the target and the substratesupport; and wherein a ratio of a diameter of the target to a height ofthe grounded shield is about 4, and wherein a ratio of a surface area ofthe grounded shield to a surface area of the target is about 1 to about1.5.

In some embodiments, a substrate processing apparatus may include achamber body having a substrate support disposed therein; a targetcoupled to the chamber body opposite the substrate support; an RF powersource to form a plasma within the chamber body; and a grounded shieldhaving an inner wall disposed between the target and the substratesupport; wherein a ratio of a diameter of the target to a height of thegrounded shield is about 4.1 to about 4.3, and wherein the ratio of thesurface area of the grounded shield to a height of the grounded shieldis about 2 to about 3.

In some embodiments, a method of processing a substrate disposed withina substrate processing chamber, wherein the substrate processing chambercomprises a chamber body and a substrate support disposed therein, themethod may include forming a plasma between a target and the substrateat a frequency of at least about 40 MHz and a pressure of about 60millitorr to about 140 millitorr, wherein the target is coupled to thechamber body opposite the substrate, which is disposed atop thesubstrate support, and wherein a grounded shield having an inner wall isdisposed between the target and the substrate support, and wherein aratio of a surface area of the grounded shield to a surface area of thetarget is about 1 to about 1.5.

Other and further embodiments of the present invention are describedbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention, briefly summarized above anddiscussed in greater detail below, can be understood by reference to theillustrative embodiments of the invention depicted in the appendeddrawings. It is to be noted, however, that the appended drawingsillustrate only typical embodiments of this invention and are thereforenot to be considered limiting of its scope, for the invention may admitto other equally effective embodiments.

FIG. 1 depicts a schematic cross sectional view of a process chamber inaccordance with some embodiments of the present invention.

FIG. 2 depicts a sectional view of a support member and surroundingstructure in accordance with some embodiments of the present invention.

FIG. 3 depicts a flow chart for a method of processing a substrate inaccordance with some embodiments of the present invention.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. The figures are not drawn to scale and may be simplifiedfor clarity. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

DETAILED DESCRIPTION

Methods and apparatus for improved physical vapor deposition (PVD)processing equipment are provided herein. In at least some embodimentsof the present invention, the improved methods and apparatus provide agrounded shield for a PVD processing apparatus that may advantageouslylower the potential difference to the grounded shield while maintainingtarget to substrate spacing, thereby facilitating PVD processing withreduced or eliminated sputtering of the grounded shield. In at leastsome embodiments, such PVD processes may advantageously be high densityplasma assisted PVD processes, such as described below.

FIG. 1 depicts a simplified, cross-sectional view of an illustrative PVDchamber 100 having a magnetron assembly in accordance with someembodiments of the present invention. The specific configuration of thePVD chamber is illustrative and PVD chambers having other configurationsmay also benefit from modification in accordance with the teachingsprovided herein. Examples of suitable PVD chambers include any of theENDURA® line of PVD processing chambers, commercially available fromApplied Materials, Inc., of Santa Clara, Calif. Other processingchambers from Applied Materials, Inc. or other manufactures may alsobenefit from the inventive apparatus disclosed herein.

In some embodiments of the present invention, the PVD chamber 100includes a chamber lid 101 disposed atop a chamber body 104 andremovable from the chamber body 104. The chamber lid 101 generallyincludes a target assembly 102 and a grounding assembly 103. The chamberbody 104 contains a substrate support 106 for receiving a substrate 108thereon. The substrate support 106 is configured to support a substratesuch that a center of the substrate is aligned with a central axis 186of the PVD chamber 100. The substrate support 106 may be located withina lower grounded enclosure wall 110, which may be a wall of the chamberbody 104. The lower grounded enclosure wall 110 may be electricallycoupled to the grounding assembly 103 of the chamber lid 101 such thatan RF return path is provided to an RF power source 182 disposed abovethe chamber lid 101. Alternatively, other RF return paths are possible,such as those that travel from the substrate support 106 via a processkit shield (e.g., a grounded shield 138 as discussed below) andultimately back to the grounding assembly 103 of the chamber lid 101.The RF power source 182 may provide RF energy to the target assembly 102as discussed below.

The substrate support 106 has a material-receiving surface facing aprincipal surface of a target 114 and supports the substrate 108 to besputter coated with material ejected from the target in planar positionopposite to the principal surface of the target 114. The substratesupport 106 may include a dielectric member 105 having a substrateprocessing surface 109 for supporting the substrate 108 thereon. In someembodiments, the substrate support 108 may include one or moreconductive members 107 disposed below the dielectric member 105. Forexample, the dielectric member 105 and the one or more conductivemembers 107 may be part of an electrostatic chuck, RF electrode, or thelike which may be used to provide chucking or RF power to the substratesupport 106.

The substrate support 106 may support the substrate 108 in a firstvolume 120 of the chamber body 104. The first volume 120 is a portion ofthe inner volume of the chamber body 104 that is used for processing thesubstrate 108 and may be separated from the remainder of the innervolume (e.g., a non-processing volume) during processing of thesubstrate 108 (for example, via the shield 138). The first volume 120 isdefined as the region above the substrate support 106 during processing(for example, between the target 114 and the substrate support 106 whenin a processing position).

In some embodiments, the substrate support 106 may be vertically movableto allow the substrate 108 to be transferred onto the substrate support106 through an opening (such as a slit valve, not shown) in the lowerportion of the chamber body 104 and thereafter raised to a processingposition. A bellows 122 connected to a bottom chamber wall 124 may beprovided to maintain a separation of the inner volume of the chamberbody 104 from the atmosphere outside of the chamber body 104. One ormore gases may be supplied from a gas source 126 through a mass flowcontroller 128 into the lower part of the chamber body 104. An exhaustport 130 may be provided and coupled to a pump (not shown) via a valve132 for exhausting the interior of the chamber body 104 and tofacilitate maintaining a desired pressure inside the chamber body 104.

An RF bias power source 134 may be coupled to the substrate support 106in order to induce a negative DC bias on the substrate 108. In addition,in some embodiments, a negative DC self-bias may form on the substrate108 during processing. In some embodiments, RF energy supplied by the RFbias power source 134 may range in frequency from about 2 MHz to about60 MHz, for example, non-limiting frequencies such as 2 MHz, 13.56 MHz,or 60 MHz can be used. In other applications, the substrate support 106may be grounded or left electrically floating. Alternatively or incombination, a capacitance tuner 136 may be coupled to the substratesupport 106 for adjusting voltage on the substrate 108 for applicationswhere RF bias power is not be desired.

The chamber body 104 further includes a grounded process kit shield(shield 138) to surround the processing, or first volume, of the chamberbody 104 and to protect other chamber components from damage and/orcontamination from processing. In some embodiments, the shield 138 maybe coupled to a ledge 140 of an upper grounded enclosure wall 116 of thechamber body 104. In other embodiments, and as illustrated in FIG. 1,the shield 138 may be coupled to the chamber lid 101, for example via aretaining ring 175.

The grounded shield 138 comprises an inner wall 143 disposed between thetarget 114 and the substrate support 106. The height of the shield 138depends upon the distance 185 between the target 114 and the substrate108. The distance 185 between the target 114 and the substrate 108, andcorrespondingly, the height of the shield 138, is scaled based on thediameter of the substrate 108. In some embodiments, the ratio of thediameter of the target 114 to the diameter of the substrate is about1.4. For example, a process chamber for processing a 300 mm substratemay have a target 114 having a diameter of about 419 mm or, in someembodiments, a process chamber for processing a 450 mm substrate mayhave a target 114 having a diameter of about 625 mm. In someembodiments, the ratio of the diameter of the target 114 to the heightof the shield 138 is about 4.1 to about 4.3, or in some embodiments,about 4.2. For example, in some embodiments of a process chamber forprocessing a 300 mm substrate, the target 114 may have a diameter ofabout 419 mm and the shield 138 may have a height of about 100 mm or, insome embodiments of a process chamber for processing a 450 mm substrate108, the target 114 may have a diameter of about 625 mm and the shield138 may have a height of about 150 mm. Other diameters and heights mayalso be used to provide the desired ratio. In process chambers havingthe ratios described above, the distance 185 between the target 114 andthe substrate 108 is about 50.8 mm to about 152.4 mm for a 300 mmsubstrate 108 or about 101.6 mm to about 203.2 mm for a 450 mmsubstrate. A process chamber having the above configurations is referredto herein as a “short throw” process chamber.

The short throw process chamber advantageously increases the depositionrate over process chambers having longer target to substrate distances185. For example, for some processes, conventional process chambershaving longer target to substrate distances provide a deposition rate ofabout 1 to about 2 angstroms/second. In comparison, for similarprocesses in a short throw process chamber, a deposition rate of about 5to about 10 angstroms/second can be obtained while maintaining highionization levels. In some embodiments, a process chamber in accordancewith embodiments of the present invention may provide a deposition rateof about 10 angstroms/second. High ionization levels at such shortspacing can be obtained by providing a high pressure, for example, about60 millitorr to about 140 millitorr, and a very high driving frequency,for example, from about 27 MHz to about 162 MHz, for example such as atabout such readily commercially available frequencies as 27.12, 40.68,60, 81.36, 100, 122, or 162.72 MHz.

However, the inventors have observed that achieving high depositionrates in conventional short throw process chambers can result in anundesirable sputtering of the grounded shield 138 caused by a highplasma potential. Sputtering of the shield 138 causes undesirablecontamination within the process chamber 100. The sputtering of theshield 138 is a result of the high voltage on the shield 138. The amountof voltage that appears on the target 114 (i.e., the powered electrode)and the grounded shield 138 (i.e., the grounded electrode) is dependenton the ratio of the surface area of the shield 138 to the surface areaof the target 114, as a greater voltage appears on the smallerelectrode. Typically, the surface area of the target 114 is larger thanthe surface area of the shield 138 resulting in a greater voltage uponthe shield 138, and in turn, resulting in the undesired sputtering ofthe shield. For example, in some embodiments of a process chamber forprocessing a 300 mm substrate 108, the target may have a diameter ofabout 419 mm with a corresponding surface area of about 138 mm² and theshield 138 may have a height of about 100 mm with a correspondingsurface area of about 132 mm² or, in some embodiments of a processchamber for processing a 450 mm substrate 108, the target may have adiameter of about 625 mm with a corresponding surface area of about 307mm² and the shield 138 may have a height of about 150 mm with acorresponding surface area of about 295,000 mm². The inventors haveobserved that in some embodiments of process chambers where the ratio ofthe surface area of the shield 138 to the surface area of the target 114is less than 1, a greater voltage is incurred upon the shield 138, whichin turn, results in the undesired sputtering of the shield. Thus, inorder to advantageously minimize or prevent the sputtering of the shield138, the inventors have observed that the surface area of the shield 138needs to be greater than the surface area of the target 114. Forexample, the inventors have observed that a ratio of the surface area ofthe shield 138 to the surface area of the target 114 of about 1 to about1.5 advantageously minimizes or prevents the sputtering of the shield138.

However, the surface area of the shield 138 cannot be increased bysimply increasing the height of the shield 138 due to the desired ratioof the diameter of the target 114 to the height of the shield 138, asdiscussed above. The inventors have observed that, in some embodimentsof a process chamber having the processing conditions discussed above(e.g., process pressures and RF frequencies used), the ratio of thesurface area of the shield 138 to the height of the shield 138 must beabout 2 to about 3 to advantageously minimize or prevent the sputteringof the shield 138. Furthermore, the diameter of the shield 138 cannot beincreased sufficiently to increase the surface area of the shield 138 toprevent sputtering of the shield 138 due to physical constraint in thesize of the process chamber. For example, an increase in the diameter ofthe shield 138 of 25.4 mm results in a surface area increase of only 6%,which is insufficient to prevent the sputtering of the shield 138.

Thus, in some embodiments, as depicted in FIG. 2, in order to obtain thedesired ratio of the surface area of the shield 138 to the surface areaof the target 114 or the required ratio of the surface area of theshield 138 to the height of the shield 138 as described above, theshield 138 includes a plurality of waves 202 comprising a concaveportion 204 and a convex portion 206, which advantageously increase thesurface area of the shield 138 by about 50% while maintaining the sameoverall height of the shield 138. For example, in some embodiments of ashort throw process chamber for processing a 300 mm substrate 108 andhaving the target diameter and shield height described above, theinclusion of a plurality of waves 202 increases the surface area of theshield 138 from about 132 mm without the plurality of waves 202 to about207 mm, while maintaining the ratio of the diameter of the target 114 tothe height of the shield 138. As a result, the ratio of the surface areaof the shield 138 to the surface area of the target 114 with theplurality of waves 202 is increased to about 1.5 and the ratio of thesurface area of the shield 138 to the height of the shield 138 isincreased to about 2. In some embodiments of a process chamberprocessing a 450 mm substrate 108 having the target diameter and shieldheight described above, the inclusion of a plurality of waves 202increases the surface area of the shield 138 from about 295 mm withoutthe plurality of waves 202 to about 463 mm while maintaining the ratioof diameter of the target 114 to the height of the shield 138. As aresult, the ratio of the surface area of the shield 138 to the surfacearea of the target 114 with the plurality of waves 202 is increased toabout 1.5 and the ratio of the surface area of the shield 138 to theheight of the shield 138 is increased to about 3.

The concave portion 204 of the waves 202 are sized to advantageouslyallow the plasma sheath to form within the concave portion 204 of eachwave 202. As such, the size of the concave portion 204 of the waves willdepend upon the frequencies used for processing. For example, in someembodiments using RF frequencies as disclosed herein (e.g., about 27 toabout 162 MHz), the period of the wave 202 is about 6 mm to about 20 mm.Increasing or decreasing the number of waves 202 in the shield 138advantageously allows for the flexibility of controlling the plasmapotential (e.g., the voltage on the shield) without changing thedistance 185 between the target 114 and the substrate 108.

Returning to FIG. 1, the chamber lid 101 rests on the ledge 140 of theupper grounded enclosure wall 116. Similar to the lower groundedenclosure wall 110, the upper grounded enclosure wall 116 may provide aportion of the RF return path between the upper grounded enclosure wall116 and the grounding assembly 103 of the chamber lid 101. However,other RF return paths are possible, such as via the grounded shield 138.

As discussed above, the shield 138 extends downwardly and may includeone or more sidewalls configured to surround the first volume 120. Theshield 138 extends along, but is spaced apart from, the walls of theupper grounded enclosure wall 116 and the lower grounded enclosure wall110 downwardly to below a top surface of the substrate support 106 andreturns upwardly until reaching a top surface of the substrate support106 (e.g., forming a u-shaped portion at the bottom of the shield 138).

A first ring 148 (e.g., a cover ring) rests on the top of the u-shapedportion (e.g., a first position of the first ring 148) when thesubstrate support 106 is in its lower, loading position (not shown) butrests on the outer periphery of the substrate support 106 (e.g., asecond position of the first ring 148) when the substrate support 106 isin its upper, deposition position (as illustrated in FIG. 1) to protectthe substrate support 106 from sputter deposition.

An additional dielectric ring 111 may be used to shield the periphery ofthe substrate 108 from deposition. For example, the dielectric ring 111may be disposed about a peripheral edge of the substrate support 106 andadjacent to the substrate processing surface 109, as illustrated in FIG.1.

The first ring 148 may include protrusions extending from a lowersurface of the first ring 148 on either side of the inner upwardlyextending u-shaped portion of the bottom of the shield 138. An innermostprotrusion may be configured to interface with the substrate support 106to align the first ring 148 with respect to the shield 128 when thefirst ring 148 is moved into the second position as the substratesupport is moved into the processing position. For example, a substratesupport facing surface of the innermost protrusion may be tapered,notched or the like to rest in/on a corresponding surface on thesubstrate support 106 when the first ring 148 is in the second position.

In some embodiments, a magnet 152 may be disposed about the chamber body104 for selectively providing a magnetic field between the substratesupport 106 and the target 114. For example, as shown in FIG. 1, themagnet 152 may be disposed about the outside of the chamber wall 110 ina region just above the substrate support 106 when in processingposition. In some embodiments, the magnet 152 may be disposedadditionally or alternatively in other locations, such as adjacent theupper grounded enclosure wall 116. The magnet 152 may be anelectromagnet and may be coupled to a power source (not shown) forcontrolling the magnitude of the magnetic field generated by theelectromagnet.

The chamber lid 101 generally includes the grounding assembly 103disposed about the target assembly 102. The grounding assembly 103 mayinclude a grounding plate 156 having a first surface 157 that may begenerally parallel to and opposite a backside of the target assembly102. A grounding shield 112 may extend from the first surface 157 of thegrounding plate 156 and surround the target assembly 102. The groundingassembly 103 may include a support member 175 to support the targetassembly 102 within the grounding assembly 103.

In some embodiments, the support member 175 may be coupled to a lowerend of the grounding shield 112 proximate an outer peripheral edge ofthe support member 175 and extends radially inward to support a sealring 181, the target assembly 102 and optionally, a dark space shield(e.g., that may be disposed between the shield 138 and the targetassembly 102, not shown). The seal ring 181 may be a ring or otherannular shape having a desired cross-section to facilitate interfacingwith the target assembly 102 and with the support member 175. The sealring 181 may be made of a dielectric material, such as ceramic. The sealring 181 may insulate the target assembly 102 from the ground assembly103.

The support member 175 may be a generally planar member having a centralopening to accommodate the shield 138 and the target 114. In someembodiments, the support member 175 may be circular, or disc-like inshape, although the shape may vary depending upon the correspondingshape of the chamber lid and/or the shape of the substrate to beprocessed in the process chamber 100. In use, when the chamber lid 101is opened or closed, the support member 175 maintains the shield 138 inproper alignment with respect to the target 114, thereby minimizing therisk of misalignment due to chamber assembly or opening and closing thechamber lid 101.

The target assembly 102 may include a source distribution plate 158opposing a backside of the target 114 and electrically coupled to thetarget 114 along a peripheral edge of the target 114. The target 114 maycomprise a source material 113 to be deposited on a substrate, such asthe substrate 108 during sputtering, such as a metal, metal oxide, metalalloy, magnetic material, or the like. In some embodiments, the target114 may include a backing plate 162 to support the source material 113.The backing plate 162 may comprise a conductive material, such ascopper-zinc, copper-chrome, or the same material as the target, suchthat RF, and optionally DC, power can be coupled to the source material113 via the backing plate 162. Alternatively, the backing plate 162 maybe non-conductive and may include conductive elements (not shown) suchas electrical feedthroughs or the like.

A conductive member 164 may be disposed between the source distributionplate and the backside of the target 114 to propagate RF energy from thesource distribution plate to the peripheral edge of the target 114. Theconductive member 164 may be cylindrical and tubular, with a first end166 coupled to a target-facing surface of the source distribution plate158 proximate the peripheral edge of the source distribution plate 158and a second end 168 coupled to a source distribution plate-facingsurface of the target 114 proximate the peripheral edge of the target114. In some embodiments, the second end 168 is coupled to a sourcedistribution plate facing surface of the backing plate 162 proximate theperipheral edge of the backing plate 162.

The target assembly 102 may include a cavity 170 disposed between thebackside of the target 114 and the source distribution plate 158. Thecavity 170 may at least partially house a magnetron assembly 196. Thecavity 170 is at least partially defined by the inner surface of theconductive member 164, a target facing surface of the sourcedistribution plate 158, and a source distribution plate facing surface(e.g., backside) of the target 114 (or backing plate 162). In someembodiments, the cavity 170 may be at least partially filled with acooling fluid, such as water (H₂O) or the like. In some embodiments, adivider (not shown) may be provided to contain the cooling fluid in adesired portion of the cavity 170 (such as a lower portion, as shown)and to prevent the cooling fluid from reaching components disposed onthe other side of the divider.

An insulative gap 180 is provided between the grounding plate 156 andthe outer surfaces of the source distribution plate 158, the conductivemember 164, and the target 114 (and/or backing plate 162). Theinsulative gap 180 may be filled with air or some other suitabledielectric material, such as a ceramic, a plastic, or the like. Thedistance between the grounding plate 156 and the source distributionplate 158 depends on the dielectric material between the grounding plate156 and the source distribution plate 158. Where the dielectric materialis predominantly air, the distance between the grounding plate 156 andthe source distribution plate 158 should be between about 5 to about 40mm.

The grounding assembly 103 and the target assembly 102 may beelectrically separated by the seal ring 181 and by one or more ofinsulators 160 disposed between the first surface 157 of the groundingplate 156 and the backside of the target assembly 102, e.g., anon-target facing side of the source distribution plate 158.

The target assembly 102 has the RF power source 182 connected to anelectrode 154 (e.g., a RF feed structure). The RF power source 182 mayinclude an RF generator and a matching circuit, for example, to minimizereflected RF energy reflected back to the RF generator during operation.For example, RF energy supplied by the RF power source 182 may range infrequency from about 13.56 MHz and to about 162 MHz or above. Forexample, non-limiting frequencies such as 13.56 MHz, 27.12 MHz, 60 MHz,or 162 MHz can be used.

In some embodiments, a second energy source 183 may be coupled to thetarget assembly 102 to provide additional energy to the target 114during processing. In some embodiments, the second energy source 183 maybe a DC power source to provide DC energy, for example, to enhance asputtering rate of the target material (and hence, a deposition rate onthe substrate). In some embodiments, the second energy source 183 may bea second RF power source, similar to the RF power source 182, to provideRF energy, for example, at a second frequency different than a firstfrequency of RF energy provided by the RF power source 182. Inembodiments where the second energy source 183 is a DC power source, thesecond energy source may be coupled to the target assembly 102 in anylocation suitable to electrically couple the DC energy to the target114, such as the electrode 154 or some other conductive member (such asthe source distribution plate 158). In embodiments where the secondenergy source 183 is a second RF power source, the second energy sourcemay be coupled to the target assembly 102 via the electrode 154.

The electrode 154 may be cylindrical or otherwise rod-like and may bealigned with a central axis 186 of the PVD chamber 100 (e.g., theelectrode 154 may be coupled to the target assembly at a pointcoincident with a central axis of the target, which is coincident withthe central axis 186). The electrode 154, aligned with the central axis186 of the PVD chamber 100, facilitates applying RF energy from the RFsource 182 to the target 114 in an axisymmetrical manner (e.g., theelectrode 154 may couple RF energy to the target at a “single point”aligned with the central axis of the PVD chamber). The central positionof the electrode 154 helps to eliminate or reduce deposition asymmetryin substrate deposition processes. The electrode 154 may have anysuitable diameter, however, the smaller the diameter of the electrode154, the closer the RF energy application approaches a true singlepoint. For example, although other diameters may be used, in someembodiments, the diameter of the electrode 154 may be about 0.5 to about2 inches. The electrode 154 may generally have any suitable lengthdepending upon the configuration of the PVD chamber. In someembodiments, the electrode may have a length of between about 0.5 toabout 12 inches. The electrode 154 may be fabricated from any suitableconductive material, such as aluminum, copper, silver, or the like.

The electrode 154 may pass through an opening in the grounding plate 156and is coupled to a source distribution plate 158. The grounding plate156 may comprise any suitable conductive material, such as aluminum,copper, or the like. Open spaces between the one or more insulators 160allow for RF wave propagation along the surface of the sourcedistribution plate 158. In some embodiments, the one or more insulators160 may be symmetrically positioned with respect to the central axis 186of the PVD chamber 100 Such positioning may facilitate symmetric RF wavepropagation along the surface of the source distribution plate 158 and,ultimately, to a target 114 coupled to the source distribution plate158. The RF energy may be provided in a more symmetric and uniformmanner as compared to conventional PVD chambers due, at least in part,to the central position of the electrode 154.

One or more portions of a magnetron assembly 196 may be disposed atleast partially within the cavity 170. The magnetron assembly provides arotating magnetic field proximate the target to assist in plasmaprocessing within the process chamber 104. In some embodiments, themagnetron assembly 196 may include a motor 176, a motor shaft 174, agearbox 178, a gearbox shaft 184, and a rotatable magnet (e.g., aplurality of magnets 188 coupled to a magnet support member 172).

The magnetron assembly 196 is rotated within the cavity 170. Forexample, in some embodiments, the motor 176, motor shaft 174, gear box178, and gearbox shaft 184 may be provided to rotate the magnet supportmember 172. In some embodiments (not shown), the magnetron drive shaftmay be disposed along the central axis of the chamber, with the RFenergy coupled to the target assembly at a different location or in adifferent manner. As illustrated in FIG. 1, in some embodiments, themotor shaft 174 of the magnetron may be disposed through an off-centeropening in the grounding plate 156. The end of the motor shaft 174protruding from the grounding plate 156 is coupled to a motor 176. Themotor shaft 174 is further disposed through a corresponding off-centeropening through the source distribution plate 158 (e.g., a first opening146) and coupled to a gear box 178. In some embodiments, one or moresecond openings 198 may be disposed though the source distribution plate158 in a symmetrical relationship to the first opening 146 toadvantageously maintain axisymmetric RF distribution along the sourcedistribution plate 158. The one or more second openings 198 may also beused to allow access to the cavity 170 for items such as sensors or thelike.

The gear box 178 may be supported by any suitable means, such as bybeing coupled to a bottom surface of the source distribution plate 158.The gear box 178 may be insulated from the source distribution plate 158by fabricating at least the upper surface of the gear box 178 from adielectric material, or by interposing an insulator layer 190 betweenthe gear box 178 and the source distribution plate 158, or the like. Thegear box 178 is further coupled to the magnet support member 172 via thegear box shaft 184 to transfer the rotational motion provided by themotor 176 to the magnet support member 172 (and hence, the plurality ofmagnets 188). The gear box shaft 184 may advantageously be coincidentwith the central axis 186 of the PVD process chamber 100.

The magnet support member 172 may be constructed from any materialsuitable to provide adequate mechanical strength to rigidly support theplurality of magnets 188. The plurality of magnets 188 may be configuredin any manner to provide a magnetic field having a desired shape andstrength to provide a more uniform full face erosion of the target asdescribed herein.

Alternatively, the magnet support member 172 may be rotated by any othermeans with sufficient torque to overcome the drag caused on the magnetsupport member 172 and attached plurality of magnets 188, for exampledue to the cooling fluid, when present, in the cavity 170.

FIG. 3 depicts a flow chart for a method 300 of processing a substratein accordance with some embodiments of the present invention. In someembodiments, at least some portions of the method 300 may be performedin a substrate processing apparatus, for example, such as the apparatus100 described above with respect to FIGS. 1 and 2. In the method 300, at302, a substrate 108 is disposed within a short throw process chamberhaving a grounded shield 138 as described above. At 304, a plasma isformed in the process chamber between the target 114 and the substrate108 at an RF frequency of about 27 MHz to about 162 MHz and a pressureof about 60 millitorr to about 140 millitorr. Next, at 306, materialsputtered from a target disposed in the short throw process chamber isdeposited on the substrate 108. The plasma formed at the above frequencyand pressure advantageously allows for a high deposition rate within theshort throw process chamber while maintaining high ionization levels. Inaddition, the design of the grounded shield 138 advantageously providesreduced sputtering of the shield during processing under suchconditions.

Thus, improved methods and apparatus for reducing the sputtering of agrounded shield in a process chamber have been disclosed herein. Theinventive apparatus may advantageously allow for an increased depositionrate in a PVD chamber, without the contamination caused by thesputtering of the grounded shield.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof.

1. A process kit shield for use in a physical vapor deposition chamber,comprising: an electrically conductive body having one or more sidewallsdefining a central opening, wherein the body has a ratio of a surfacearea of inner facing surfaces of the one or more sidewalls to a heightof the one or more sidewalls of about 2 to about
 3. 2. The process kitshield of claim 1, wherein the electrically conductive body is annular.3. The process kit of claim 1, wherein the electrically conductive bodyis fabricated from one or more of an aluminum alloy or stainless steel.4. The process kit of claim 1, wherein at least one of the one or moresidewalls of the electrically conductive body further comprisesalternating concave and convex portions.
 5. The process kit of claim 4,wherein a period of the concave portions is about 6 mm to about 20 mm.6. The process kit of claim 4, wherein each of the concave portions isconfigured to allow a plasma sheath to form within the concave portionat an RF frequency of about 27 MHz to about 162 MHz and at chamberpressure of about 60 millitorr to about 140 millitorr.
 7. The processkit of claim 1, wherein at least one of the one or more sidewalls of theelectrically conductive body of the process kit shield includes aplurality of waves disposed between a target and a substrate support ofa process chamber in which the process kit is inserted.
 8. The processkit of claim 7, wherein the plurality of waves is arranged in arepeating pattern, and wherein each wave has a period of about 6 mm toabout 20 mm.
 9. A substrate processing apparatus, comprising: a chamberbody having a substrate support disposed therein; a target coupled tothe chamber body opposite the substrate support; an RF power source toform a plasma within the chamber body; and a process kit shield havingan electrically conductive body, the electrically conductive body havingone or more sidewalls defining a central opening, wherein theelectrically conductive body has a ratio of a surface area of innerfacing surfaces of the one or more sidewalls to a height of the one ormore sidewalls of about 2 to about
 3. 10. The substrate processingapparatus of claim 9, wherein a ratio of the diameter of the target tothe diameter of a substrate disposed atop the substrate support is about1.4.
 11. The substrate processing apparatus of claim 9, wherein at leastone of the one or more sidewalls of the electrically conductive body ofthe process kit shield includes a plurality of waves disposed betweenthe target and the substrate support.
 12. The substrate processingapparatus of claim 11, wherein the plurality of waves comprisesalternating concave and convex portions.
 13. The substrate processingapparatus of claim 12, wherein a period of the concave portions is about6 mm to about 20 mm.
 14. The substrate processing apparatus of claim 12,wherein each of the concave portions is configured to allow a plasmasheath to form within the concave portion at an RF frequency of about 27MHz to about 162 MHz and at chamber pressure of about 60 millitorr toabout 140 millitorr.
 15. The substrate processing apparatus of claim 11,wherein the plurality of waves is arranged in a repeating pattern, andwherein each wave has a period of about 6 mm to about 20 mm.
 16. Thesubstrate processing apparatus of claim 9, wherein a ratio of a diameterof the target to a height of the grounded shield is about 4.1 to about4.3, and wherein a ratio of a surface area of inner facing surfaces ofthe inner sidewall to a surface area of a principal surface of thetarget is about 1 to about 1.5.
 17. The substrate processing apparatusof claim 9, wherein the electrically conductive body of the process kitshield is annular.
 18. The substrate processing apparatus of claim 9,wherein the electrically conductive body of the process kit shield isfabricated from one or more of an aluminum alloy or stainless steel. 19.The substrate processing apparatus of claim 9, wherein a distancebetween the target and a substrate having a diameter of 300 mm disposedatop the substrate support is about 50.8 mm to about 152.4 mm.
 20. Thesubstrate processing apparatus of claim 9, wherein a distance betweenthe target and a substrate having a diameter of 450 mm disposed atop thesubstrate support is about 101.6 mm to about 203.2 mm.